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Original Caption Released with Image:

MGS MOC Release No. MOC2-445, 7 August 2003

Tithonium Chasma is one of the troughs of the vast Valles Marineris canyon system. Within many of these troughs are outcrops of light-toned, layered, sedimentary rock. This Mars Global Surveyor (MGS) Mars Orbiter Camera (MOC) image shows eroded sedimentary rock exposures overlain by the remnants of a smoother-surfaced, dark material. The dark feature is a younger sedimentary deposit made of a different material than the light-toned sediments; it covered the lighter rocks after they were eroded to their present form. This area is located near 5.0°S, 89.8°W. Sunlight illuminates the scene from the lower left.